- A
The application tier instances do not have a route to the web tier instances.
Why wrong: Route tables are correctly configured per the scenario, and DNS resolution works.
- B
The application tier security group's inbound rule is stateful, but the outbound rule is not configured to allow return traffic.
Why wrong: Security groups are stateful; outbound return traffic is automatically allowed.
- C
The web tier security group's outbound rules do not allow traffic to the application tier security group.
If the web tier security group does not have an outbound rule allowing traffic to the application tier, connections will fail.
- D
The network ACL for the private subnet is blocking inbound traffic from the public subnet.
Why wrong: NACLs are stateless; if they are not configured correctly, they could block traffic, but the question does not indicate NACL misconfiguration.
ANS-C01 Network Security, Compliance and Governance Practice Question
This ANS-C01 practice question tests your understanding of network security, compliance and governance. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has deployed a multi-tier application in a VPC with public and private subnets. The web tier runs on EC2 instances in public subnets, and the application tier runs on EC2 instances in private subnets. The application tier must only accept traffic from the web tier security group. The security group for the application tier has an inbound rule allowing HTTP traffic from the web tier security group. However, the application team reports that the web tier instances cannot connect to the application tier instances. The network administrator has verified that the web tier instances can resolve the private DNS names of the application tier instances, and the route tables are correctly configured. What is the MOST likely cause of the connectivity issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The web tier security group's outbound rules do not allow traffic to the application tier security group.
Security groups are stateful, meaning that if you allow inbound traffic, the return traffic is automatically allowed regardless of outbound rules. However, the outbound rules of the initiating security group (the web tier) must permit the traffic to reach the destination. Since the web tier instances initiate the connection to the application tier, the web tier security group's outbound rules must allow HTTP traffic to the application tier security group. If those outbound rules are missing or too restrictive, the connection will fail even though the application tier's inbound rule is correct.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The application tier instances do not have a route to the web tier instances.
Why it's wrong here
Route tables are correctly configured per the scenario, and DNS resolution works.
- ✗
The application tier security group's inbound rule is stateful, but the outbound rule is not configured to allow return traffic.
Why it's wrong here
Security groups are stateful; outbound return traffic is automatically allowed.
- ✓
The web tier security group's outbound rules do not allow traffic to the application tier security group.
Why this is correct
If the web tier security group does not have an outbound rule allowing traffic to the application tier, connections will fail.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The network ACL for the private subnet is blocking inbound traffic from the public subnet.
Why it's wrong here
NACLs are stateless; if they are not configured correctly, they could block traffic, but the question does not indicate NACL misconfiguration.
Common exam traps
Common exam trap: answer the scenario, not the keyword
AWS often tests the misconception that security groups are stateless like network ACLs, leading candidates to incorrectly assume that outbound rules on the destination security group are needed for return traffic, when in fact the issue is the outbound rules on the source security group.
Trap categories for this question
Scenario analysis trap
Route tables are correctly configured per the scenario, and DNS resolution works.
Detailed technical explanation
How to think about this question
Security groups operate at the instance level and are stateful, meaning that if you allow inbound HTTP (TCP port 80) from a source security group, the response traffic (TCP ports ephemeral 1024-65535) is automatically allowed back to the source. However, the initiating security group (web tier) must have an outbound rule that permits traffic to the destination security group; without it, the initial SYN packet is dropped. This is a common misconfiguration because engineers often focus only on the inbound rules of the target, forgetting that the source's outbound rules must also permit the traffic.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Network Security, Compliance and Governance — study guide chapter
Learn the concepts, then practise the questions
- →
Network Security, Compliance and Governance practice questions
Targeted practice on this topic area only
- →
All ANS-C01 questions
1,705 questions across all exam domains
- →
AWS Certified Advanced Networking Specialty ANS-C01 study guide
Full concept coverage aligned to exam objectives
- →
ANS-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related ANS-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network Management and Operations practice questions
Practise ANS-C01 questions linked to Network Management and Operations.
Network Security, Compliance and Governance practice questions
Practise ANS-C01 questions linked to Network Security, Compliance and Governance.
Network Design practice questions
Practise ANS-C01 questions linked to Network Design.
Network Implementation practice questions
Practise ANS-C01 questions linked to Network Implementation.
ANS-C01 fundamentals practice questions
Practise ANS-C01 questions linked to ANS-C01 fundamentals.
ANS-C01 scenario practice questions
Practise ANS-C01 questions linked to ANS-C01 scenario.
ANS-C01 troubleshooting practice questions
Practise ANS-C01 questions linked to ANS-C01 troubleshooting.
Practice this exam
Start a free ANS-C01 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this ANS-C01 question test?
Network Security, Compliance and Governance — This question tests Network Security, Compliance and Governance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The web tier security group's outbound rules do not allow traffic to the application tier security group. — Security groups are stateful, meaning that if you allow inbound traffic, the return traffic is automatically allowed regardless of outbound rules. However, the outbound rules of the initiating security group (the web tier) must permit the traffic to reach the destination. Since the web tier instances initiate the connection to the application tier, the web tier security group's outbound rules must allow HTTP traffic to the application tier security group. If those outbound rules are missing or too restrictive, the connection will fail even though the application tier's inbound rule is correct.
What should I do if I get this ANS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More ANS-C01 practice questions
- A company is designing a network security architecture for a multi-account environment using AWS Transit Gateway. The se…
- A company is using AWS Direct Connect to connect its on-premises network to AWS. The company wants to encrypt all traffi…
- A company uses AWS Transit Gateway to connect multiple VPCs and on-premises networks via AWS Site-to-Site VPN. The secur…
- A global e-commerce company uses a hub-and-spoke network topology with a transit VPC in us-east-1. Each spoke VPC has an…
- A company is designing a multi-VPC architecture in the same region. The VPCs need to communicate with each other using p…
- A company is deploying an application that requires low-latency communication between EC2 instances in two different AWS…
Last reviewed: Jun 30, 2026
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ANS-C01 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.